According to the 2011 Census of India, the population of the Tezu urban area was 18,184. The broader Lohit district has seen steady population growth, though the town itself remains relatively small and community-oriented.
The population is highly diverse. The indigenous Mishmi tribes (Digaru and Miju) form a significant portion of the populace. There is also a substantial Tibetan community residing in the designated settlements. Additionally, Tezu is home to government employees, defense personnel, and business people from various other parts of India (such as Assam, Bihar, and West Bengal).
Religious affiliations include Animism (Donyi-Polo and traditional Mishmi beliefs), Hinduism, Buddhism (practiced largely by the Tibetan community and some local tribes), and Christianity. The primary languages spoken are Mishmi, Hindi, English, Assamese, and Tibetan. Hindi serves as the dominant lingua franca connecting the diverse communities.